On the entropy of strings and branes

Abstract We show that the entropy of strings that wind around the Euclidean time circle is proportional to the Noether charge associated with translations along the T-dual time direction. We consider an effective target-space field theory which includes a large class of terms in the action with vari...

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Main Authors: Ram Brustein, Yoav Zigdon
Format: Article
Language:English
Published: SpringerOpen 2022-10-01
Series:Journal of High Energy Physics
Subjects:
Online Access:https://doi.org/10.1007/JHEP10(2022)112
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author Ram Brustein
Yoav Zigdon
author_facet Ram Brustein
Yoav Zigdon
author_sort Ram Brustein
collection DOAJ
description Abstract We show that the entropy of strings that wind around the Euclidean time circle is proportional to the Noether charge associated with translations along the T-dual time direction. We consider an effective target-space field theory which includes a large class of terms in the action with various modes, interactions and α′ corrections. The entropy and the Noether charge are shown to depend only on the values of fields at the boundary of space. The classical entropy, which is proportional to the inverse of Newton’s constant, is then calculated by evaluating the appropriate boundary term for various geometries with and without a horizon. We verify, in our framework, that for higher-curvature pure gravity theories, the Wald entropy of static neutral black hole solutions is equal to the entropy derived from the Gibbons-Hawking boundary term. We then proceed to discuss horizonless geometries which contain, due to the back-reaction of the strings and branes, a second boundary in addition to the asymptotic boundary. Near this “punctured” boundary, the time-time component of the metric and the derivatives of its logarithm approach zero. Assuming that there are such non-singular solutions, we identify the entropy of the strings and branes in this geometry with the entropy of the solution to all orders in α′. If the asymptotic region of an α′-corrected neutral black hole is connected through the bulk to a puncture, then the black hole entropy is equal to the entropy of the strings and branes. Later, we discuss configurations similar to the charged black p-brane solutions of Horowitz and Strominger, with the second boundary, and show that, to leading order in the α′ expansion, the classical entropy of the strings and branes is equal exactly to the Bekenstein-Hawking entropy. This result is extended to a configuration that asymptotes to AdS.
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spelling doaj.art-95b766ee3a074663862f42020f5faab42022-12-22T02:37:22ZengSpringerOpenJournal of High Energy Physics1029-84792022-10-0120221013010.1007/JHEP10(2022)112On the entropy of strings and branesRam Brustein0Yoav Zigdon1Department of Physics, Ben-Gurion UniversityDepartment of Physics, Ben-Gurion UniversityAbstract We show that the entropy of strings that wind around the Euclidean time circle is proportional to the Noether charge associated with translations along the T-dual time direction. We consider an effective target-space field theory which includes a large class of terms in the action with various modes, interactions and α′ corrections. The entropy and the Noether charge are shown to depend only on the values of fields at the boundary of space. The classical entropy, which is proportional to the inverse of Newton’s constant, is then calculated by evaluating the appropriate boundary term for various geometries with and without a horizon. We verify, in our framework, that for higher-curvature pure gravity theories, the Wald entropy of static neutral black hole solutions is equal to the entropy derived from the Gibbons-Hawking boundary term. We then proceed to discuss horizonless geometries which contain, due to the back-reaction of the strings and branes, a second boundary in addition to the asymptotic boundary. Near this “punctured” boundary, the time-time component of the metric and the derivatives of its logarithm approach zero. Assuming that there are such non-singular solutions, we identify the entropy of the strings and branes in this geometry with the entropy of the solution to all orders in α′. If the asymptotic region of an α′-corrected neutral black hole is connected through the bulk to a puncture, then the black hole entropy is equal to the entropy of the strings and branes. Later, we discuss configurations similar to the charged black p-brane solutions of Horowitz and Strominger, with the second boundary, and show that, to leading order in the α′ expansion, the classical entropy of the strings and branes is equal exactly to the Bekenstein-Hawking entropy. This result is extended to a configuration that asymptotes to AdS.https://doi.org/10.1007/JHEP10(2022)112Black Holes in String TheoryLong StringsTachyon Condensation
spellingShingle Ram Brustein
Yoav Zigdon
On the entropy of strings and branes
Journal of High Energy Physics
Black Holes in String Theory
Long Strings
Tachyon Condensation
title On the entropy of strings and branes
title_full On the entropy of strings and branes
title_fullStr On the entropy of strings and branes
title_full_unstemmed On the entropy of strings and branes
title_short On the entropy of strings and branes
title_sort on the entropy of strings and branes
topic Black Holes in String Theory
Long Strings
Tachyon Condensation
url https://doi.org/10.1007/JHEP10(2022)112
work_keys_str_mv AT rambrustein ontheentropyofstringsandbranes
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